Spearman's rank correlation

Spearman's rank correlation is a statistical method used to measure the strength and direction of the relationship between two variables based on their ranks rather than their actual values. It evaluates how well the order of one set of data matches the order of another set, indicating whether higher values in one correspond to higher in the other (positive correlation) or lower (negative correlation). This approach is useful when data are not evenly spaced or when relationships are non-linear, providing a clear sense of how two variables are associated without assuming a specific mathematical form.